1. Field of the Invention
This invention relates to the production of novel anti-static fabric softeners or softening compositions derived from certain select amphoteric surface active agents and processes for their use. The novel anti-static fabric softeners or softening compositions of this invention are especially useful in imparting excellent softening and static elimination of the dried clothes without the adversities of common fabric softeners. The quality of softness or being soft is well defined in the art and, as used herein, means that quality of a treated fabric whereby its texture is smooth, pliable, and fluffy, and not rough or scratchy to the touch. The term "harshness" is defined as the converse or opposite of "softness." Modern heavy duty laundry detergents generally turn fabrics "harsh" particularly after a few launderings. This is partly because such laundering operations usually remove the soft oily "finish" from the fabric and partly because they cause deposition of scratchy inorganic salts such as Ca/Mg carbonates, phosphates, etc. on the fabric. To restore the pliable soft touch to the fabrics, the so-called "fabric softeners" have been incorporated into the laundering operation.
There is still another, and even more notorious problem that is faced in ordinary laundering operations. This is called "static cling" of the dried fabrics and is particularly a problem with modern synthetic fabrics. Static cling is, generally, the phenomenon of one fabric adhering to another or to parts of itself or to the walls of the dryer as a result of static electrical charges located on the surface of the fabric. It can also involve the adherence of lint, dust, and other similarly undesired substances to a fabric, owing to these static charges. It is noticeably present in fabrics that are freshly washed and dried in an automatic dryer. However, softening and reducing the static cling of fabrics makes such fabrics more comfortable when worn and easier to iron since they develop fewer wrinkles, which wrinkles are hard to iron. With larger and larger quantities of synthetic fabrics in the daily laundry load, static cling has become of late a big nuisance, since it seriously interferes with the manageability of the dry clothes and their wearing comfort. Although static is not a new problem with textiles, it did not assume much importance prior to the introduction of hydrophobic fibers. The hygroscopic nature of hydrophilic fiber furnishes sufficient moisture to conduct away any electrical charge generated. The low vapor absorbency of hydrophobic fibers and finishes, however, does not produce electrical conductors with which to disperse static.
In principle, coating a "harsh" fabric surface with "fatty" or "oily" material to impart sufficient lubrication should render it soft to touch. But large quantities of such material are generally required to impart such effect, and such large quantities generally mask the natural feel of the fiber and give it an undesirable "greasy soft," rather than an agreeable "fluffy soft," feel.